Compression tester

ABSTRACT

A pressure indicating gauge which utilizes a piston responsive to test pressure to move a diagonally oriented indicator along a longitudinal axis. A display having a transverse slot is located adjacent the indicator. As the diagonally oriented indicator moves longitudinally, it undergoes an apparent transverse travel along the slot, and pressure indicia adjacent the slot provide an indication of the magnitude of the test pressure.

United States Patent [1 1 Holtzman Dec. 18, 1973 COMPRESSION TESTER3,320,801 5/1967 Rhindress 73/47 X [75] Inventor: Norman Holtzman, LosAngeles,

Cahf- Primary ExaminerDonald O. Woodiel [73] Assignee: Orion Industries,Inc., Los Angeles, Attorney-Francs Utecht et Calif.

[22] Filed: Oct. 30, 1972 [57] ABSTRACT [21] App]. No.1 302,292

I A pressure indicator or gauge which utilizes a piston responsive totest pressure to move diagonally 73/419 73/1 'oriented indicator along alongitudinal axis. A display [58] Fie'ld H 6 47 having a transverse slotis located adjacent the indi- 73l4l9 cator. As the diagonally orientedindicator moves 1 R longitudinally, it undergoes an apparent transversetravel along the slot, and pressure indicia adjacent [56] ReferencesCited the slot provide an indication of the magnitude of UNITED STATESPATENTS t i uifi lf a 1 2,620,656 l2/l952 Peterson 73/47 X 6 Claims, 6Drawing Figures PATENTED DEC] 81975 SHEEIIOFZ Flex llllllllllllllll lllJill! QIUVITFPP I 1 COMPRESSION TESTER BACKGROUND OF THE INVENTION 1.Field of the Invention The present inventionrelates to compressiontesters, and particularly compression testers for determining cylinderhead pressures in an internal combustion piston engine.

2. Description of the Prior Art Mostconventional compression testersutilize a valve core which outwardly projects an indicator in proportionto the cylinder head pressure sensed, or utilize a pressure sensitiveelement operative to rotate an indicator needle or the like past apressure indicia display. These devices are relatively expensive,sometimes fragile, and usually difficult to read.

SUMMARY OF THE INVENTION According to the present invention, acompression tester is provided which employs a piston carrying adiagonal indicator movable longitudinally with the piston in response tocylinder head pressure. The tester includes a display having a viewingopening or slot extending generally normal or transversely of thelongitudinal axis of movement of the piston. The diagonal indicatorregisters with the display slot and appears to traverse the length ofslot upon longitudinal movement of the indicator. The diagonal indicatormay simply be a line, or be defined as the line of demarcation betweenareas of different color. The latter arrangement is preferred becausevivid, contrasting colors may be selected to greatly facilitate readingof the tester.

The tester is adapted to be fitted with a resilient, relatively fixedconnector end which can be pressed into sealing relation against theusual spark plug port, or it may be provided with a flexible connectorhose mounting a threaded fitting at the end for screwing into the sparkplug port.

The compression tester is easy to handle and read, rugged, andrelatively inexpensive.

A holding valve is provided in the tester to hold or trap the testpressure and maintain the pressure indication long enough so that theuser can remove the tester and read it. A release element is operable tounseat the holding valve and thereby release the test pressure to readythe tester for further use.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of acompression tester according to the present invention;

FIG. 2 is a front elevational view of another embodiment, similar to theembodiment of FIG. 1, except that it utilizes a flexible connector hoserather than a fixed connector end;

FIG. 3 is a front elevational view of the display and indicator portionsof the, tester of FIG. 1, illustrating their positions in the absence oftest pressure;

FIG. 4 is a view taken along the line 4-4 of FIG. 1;

FIG. 5 is an enlarged view taken along the line 5-5 of FIG. 4; and

FIG. 6 is a view similar to FIG. 3, but illustrating the position of theindicator when a test pressure exists.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings,and particularly to FIGS. 1 and 3 through 6, there is illustrated acompression tester 10 comprising, generally, a T-shape body or case 12;a piston 14 movable longitudinally in an elongated cylinder 16 definedby a stem 18 carried in the vertical leg or lower portion 19 of the case12; bias 5 means in the form of a compression spring 20 operative tourge the piston 14 longitudinally in a direction opposite movement ofthe piston 14 in response to test pressure; a display 22 mounted in thetransverse or upper portion 23 of the case 12 and defining a slot 24extending transversely or generally normal to the axis of the cylinder16; and an indicator 26 carried by the piston 14 and movablelongitudinally therewith in adjacent relation to the slot 24, therelative movement of the indicator 26 with respect to the slot 24yielding an indication of the extent of longitudinal movement of thepiston 14 in response to a test pressure.

The compression tester 10 is of that type used by garage mechanics andindividual car owners to determine cylinder head pressures, and isadapted to be mounted to the spark plug port (not shown) of theparticular cylinder being tested. The compression tester 10 is adaptedto be hand-held in position over the spark plug port. Anotherembodiment, that shown in FIG. 2, is very similar to the tester 10except that, as will be seen, it includes a flexible hose 28 whichmounts a screw adaptor 30 for threaded coupling to the spark plug port.The embodiment of FIG. 2 will be described in greater detail later.

With respect to the compression tester 10, the case 12 is preferably.injection molded in front and rear halves secured together in anysuitable manner to define a hollow interior. The interior is generallydivided I into a substantially rectangular upper compartment 32 and agenerally cylindrical lower compartment 34.

A series of transverse ribs 36, 38, and 42, each having a circularcentral opening, are integrally formed in the halves of the case 12during molding. The elongated, generally cylindrical stem 18 fits withinand is located by the ribs, and a reduced diameter stem portion 44projects outwardly of the casing from the central opening in the rib 42.A shoulder 46 defined by the change in cross section of the stem 18 atthe portion 44 rests upon the upper surface of the rib 40 to maintin thestem 18 in position.

A metal ferrule 48 is press-fitted about the case lower portion 19 toprotect the plastic material of the case 12 from abuse, the ferrule 48including a central opening through which the stem lower portion 44projects.

A resilient, centrally bored end fitting 50 made of rubber or the likeis press-fitted onto the projecting end of the stem lower portion 44,and because of its resilience is adapted to be forcibly seated insealing relation upon a conventional spark plug port. The central borein the fitting 50 and the communicating cylinder 16 constitute thepressure inlet to the tester.

The lower portion of the cylinder 16 is reduced in diameter, defining aseat 52 upon which is disposed a usual O-ring 54 for sealing. An annularflange S6 of a holding valve 58 rests upon the O-ring 54, and anintegral, longitudinally extending valve stem 60 thereof extendsdownwardly through the O-ring 54.

The lower end of the stem 60 is rounded and normally in opposition orregistry with a transverse passage 62 provided in the stem 60. A releasevalve 61 is transversely movable in the passage 62, and a reduceddiameter inner portion 64 thereof projects into the cylinder 16 belowthe lower end of the holding valve stem 60.

The front half of the case 12 is molded to include a protuberant portion63 having an opening through which the button or outer end of therelease valve 61 extends, the outer end of the valve constituting abutton which can be pressed inwardly to effect engagement with andupward movement of the holding valve 58. This unseats the flange 56 ofthe valve 58 from sealing engagement with the underlying O-ring 54.

The release valve 61 includes an annular flange 66 which engages theinner face of the margins defining the opening in the protuberantportion 63 to thereby constrain the valve 61 from coming out ofposition. A fluid tight seal is provided between the valve 61 and thepassage 62 by an O-ring 68 fitted about the valve inner portion 64.

The holding valve 58 is normally biased downwardly into sealingengagement with'the seat 52 by a compression spring '70 which isinterposed between the holding valve flange 56 and the lower end of thepiston 14. As will be seen, development of a test pressure at thepressure inlet of the tester has the effect of rasing the holding valve58 against the bias of the spring 70, permitting this pressure to thendevelop against the piston 44 for upward movement thereof. However, whenthe test pressure at the pressure inlet drops, the holding valve 58abruptly descends and seats, trapping or holding the test pressurewithin the upper portion of the cylinder 16 so that its effect upon thepiston 14 can be maintained for an interval sufficient to allow the userto read the tester at his leisure.

Depression or inward movement of the release valve 61 causes the innerportion 64 thereof to engage the lower end of the holding valve stem 60,unseating the valve 58 and thereby allowing any built-up pressure in thecylinder upper portion 16 to escape downwardly and out of the testerpressure inlet at the lower end.

The piston 14 is preferably injection molded of rugged plastic or thelike and includes a lower piston rod portion 71 of cruciform sectionhaving an annulus at its lower extremity which receives an O-ring 72 toprevent pressure loss past the piston 14. An upper piston rod portion 74of heavier cross-section constitutes a spring retainer which isseparated from the lower rod portion by a generally rectangular,transversely oriented platform 76. As best seen in FIG. 4, a pair oflongitudinally or vertically oriented walls 78 are integrally joined toside edges of the platform 76 and include front edges which areintegrally attached to and support a generally rectangular indicatorplate 80.

The lower end of the. compression spring 20, which is made of highquality music wire or the like, is disposed upon and is retained inposition by the upper piston rod portion 74, and bears against theplatform 76. The upper end of the spring bears against an annular flange84 forming a part of an adjustment screw 86 which extends upwardlythrough an opening 88 molded in the case 12. An annulus 90 incommunication with the opening 88 is also molded in the case 12, andreceives a threaded nut 92 for threadable cooperation with an externallythreaded, upwardly extending shank 94 of the screw 86. The upper end ofthe shank 94 includes a screw driver slot 96 by means of which the screw86 can be rotated to adjust the effective spring force exerted by thespring 82.

As best seen in FIG. 4, the face of the rectangular indicator plate 80is provided with paint, decalcomania,

or the like of contrasting colors which adjoin to define a diagonallyoriented indicator line 98.

The upper edge of the plate is normally located below the casetransverse slot 24 so that the indicator line 98 is not visible throughthe slot 24. However, when the piston 14 rises in response to a pressureat the tester pressure inlet, the indicator line 98, as best seen inFIG. 6, becomes visible through the slot 24 and appears to travel to theleft along the slot 24 as the upward movement of the piston 14 andindicator plate 80 continues.

The slot 24 is integrally molded in a recessed portion of the case 12,as best seen in FIG. 5, and an indicia plate 100 forming part of thedisplay 22 is suitably mounted within this recessed portion in overlyingrelation to the slot 24. The plate 100 includes a slot 102 in registrywith the slot 24, and also includes a series of indicia 104 and 106above and below the slot 102, respectively, as best seen in FIGS. 3 and6.

A complementally shaped transparent cover or lens 108 is fitted inoverlying relation to the plate 100 to protect the plate 100 and theinterior of the case 12 from the elements.

In operation, the spark plug of the particular cylinder to be tested isremoved and the rubber fitting 50 of the tester is pressed firmlyagainst the spark plug port. The engine is turned or cranked to bringthe engine piston upwardly to develop the cylinder head pressure at thetester pressure inlet. This developed pressure is constrained againstescape past the release valve 61 by the O-ring 68, and instead actsagainst the holding valve 58, raising it off its seat 52 against thebias of the spring 70. This enables the test pressure to act against thelower end of the piston 14 to raise the piston 14 against the bias ofthe spring 20. This causes the diagonal indicator line 98 to appear totravel transversely along the length of the slot 102, and the indicia104 or 106 yield an indication of the extent of the upward travel of thepiston 14. This is substantially directly proportional to the magnitudeof the test pressure.

The adjustment screw 86 is rotatable to adjust the force developed bythe compression spring 20 to compensate for any discrepancies which maydevelop over the life of the tester.

Referring now to FIG. 2, a compression tester 110 is illustrated whichis substantially identical to the tester 10 except for the manner ofcoupling the tester 110 to the sprak plug port. Like numerals are usedto designate like parts for the two embodiments.

The tester 1 10 is not provided with a resilient end fitting 50, butinstead includes a hose fitting 112 which crimps one end of the flexiblehose 28 onto the projecting stern lower portion 44. A similar fitting116 is utilized to crimp the opposite end of the hose onto a shankportion (not shown) of the screw adaptor 30. The adaptor is centrallybored and includes threaded portions 120 and 122 which allow the adaptorto be threaded into either standard 14mm or 18mm spark plug ports. Asealing washer 124 and a sealing O-ring 126 are carried by the adaptor30 to insure a fluid tight connection when the adaptor 118 is screwedinto position within the spark plug port of the cylinder being tested.

From the foregoing it is seen that the present compression testers M andll 10 are rugged in construction, relatively maintenance free inoperation. The configuration of the testers is such that they are easilyheld and handled by the user, and the orientation of the indicia 104 and106 is such that readings can easily be taken without having to reorientthe tester from its test position. The release valve 61 is handy so thatit can be easily operated to vent pressure from a previous test to readythe tester for the next test. The diagonal indicator line 98 affords aclearly visible and easily readable display'of the magnitude of the testpressure, and such indicia 104 and 106 may, for convenience, compriseEnglish and metric calibrations, respectively.

Various modifications and changes may be made with regard to theforegoing detailed description without departing from the spirit of theinvention.

I claim:

1. A compression tester comprising:

means defining an elongated cylinder having a pressure inlet at oneextremity;

a piston movable longitudinally in said cylinder in response to testpressure developed at said pressure inlet;

bias means tending to urge said piston longitudinally in a directionopposite the movement of said piston in response to said test pressure;

display means carried by said first-mentioned means adjacent theextremity of said cylinder opposite said pressure inlet, and defining aviewing slot extending across said display means generally normal to theaxis of said cylinder, said display means including indicia disposedalong said slot; and indicator means carried by said piston and movabletherewith adjacent said slot, said indicator means defining an indicatorline extending diagonally relative to said slot whereby said indicatorline undergoes an apparent transverse travel along said slot uponlongitudinal movement of said indicator means with said piston.

2. A compression tester according to claim 1 wherein saidfirst-mentioned means comprises a T-shape, hollow case and an elongatedstem received within the vertical leg of the T, said stem including acentral bore constituting said cylinder.

3. A compression tester according to claim 1 wherein saidfirst-mentioned means comprises an elongated stem having a lowerextremity adapted for disposition within the central bore of a fittingcooperative with a spark plug port.

4. A compression tester according to claim 1 and including screwadjustment means carried by said case and in engagement with said biasmeans, said screw adjustment means being operable to compress said biasmeans and thereby adjust the force exerted by said bias means againstsaid piston.

5. A compression tester according to claim 1 wherein said cylinderincludes a seat, and wherein said tester further comprises holding valvemeans upon said seat, and holding bias means urging said holding valvemeans onto said seat, whereby test pressure is retained between saidpiston and said holding valve means.

6. A compression tester according to claim 5 and in cluding releasevalve means carried by said case in en gagement with said holding valvemeans and selectively operable to move and unseat said holding valvemeans from said seat to enable said test pressure to escape.

* l= ll Disclaimer 3,779,081.N0rman Holtzman, Los Angeles, Calif.COMPRESSION TESTER. Patent dated Dec. 18,

1973. Disclaimer filed Mar. 29, 1989, by the assignee, Mr. Gasket C0.

Hereby enters this disclaimer to the entire term of said patent.

[Ofiicial Gazette May 23, I 989 UNITED STATES OF FICE CERTIFICATE OFCORRECTION Patent 3.779Jo81 D d necembe ls, 1973 lnv Norman Holt zman Itis certified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

In the cover page, item [54] delete "COMPRESSION TESTER" and insertPRESSURE GAUGE In Column 1, line 1, delete "COMPRESSION TESTER" andinsert PRESSURE GAUGE lines 4-7, delete "compression testers, andparticularly compression testers for determining cylinder head pressuresin an internal combustion piston engine" and insert pressure indicatorsor gauges line 9, delete "compression testers" and insert pressuregauges line 11, delete "cylinder head" and insert magnitude of the lines17-18, delete "compression tester" and insert pressure indicator orgauge line 20, delete "cylinder head" and insert the test line 31,delete "The tester" and insert One embodiment of the present gauge line33, after "port", insert of an .internal combustion engine line 35delete "compression tester" and insert pressure gauge line 50 deletecompression tester" and insert pressure gauge line 5 delete "tester" andinsert gauge and line 63,

delete "compres-"and insert pressure indicator or gauge In Column 2,line 1, delete "sion tester"; line 17, delete FORM PO-IOSO (10-69)USCOMM-DC 80375-P69 ".5. GOVERNMENT PRINTING OFFICE I!" 0-3.5-331,

Patent No. 3,779,081 Dated December 18, 1973 Invent0r($) Norman HoltzmanI PAGE 2 It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

"compression tester 10 is of that type" and insert pressure gaugedescribed herein by way of example may be line 19 delete "and is" andinsertbeing line 21, delete "compression tester" and insert pressuregauge line 24, delete "tester" and insert gauge line 29, delete"compression tester" and insert gauge line 55, delete "tester" andinsert gauge In Column 3, line 21, delete "tester" and insert gauge InColumn 4, line 26, delete "tester" and insert gauge line 45, delete"compression tester" and insert pressure gauge lineSO, delete "tester."and insert gauge line 64, delete "com-" and insert pressure gauges line65, delete "pression testers"; line 67, delete "testers" and insertgauges In Column 5, line 15, delete "compression tester" and insertpressure gauge line 10, delete "compression tester" and insert pressuregauge line 15, delete "compression tester" and insert pressure gaugeline 21, delete 'compression tester" and insert pressure gauge line 27,delete "compression tester" and insert pressure gauge Signed and sealedthis 15th day of April 1975.

strum latt-TBSt:

C. --=L D."-;;-BZ HUT? C. 11330)? Commissioner of Patents --:t:stin;Officer and Trademarks M PC4050 (IO-69) USCOMM-DC 6O876-P69 11.5,GOVERNMENT PRINTING OFFICE ll, O-365-334,

1. A compression tester comprising: means defining an elongated cylinderhaving a pressure inlet at one extremity; a piston movablelongitudinally in said cylinder in response to test pressure developedat said pressure inlet; bias means tending to urge said pistonlongitudinally in a direction opposite the movement of said piston inresponse to said test pressure; display means carried by saidfirst-mentioned means adjacent the extremity of said cylinder oppositesaid pressure inlet, and defining a viewing slot extending across saiddisplay means generally normal to the axis of said cylinder, saiddisplay means including indicia disposed along said slot; and indicatormeans carried by said piston and movable therewith adjacent said slot,said indicator means defIning an indicator line extending diagonallyrelative to said slot whereby said indicator line undergoes an apparenttransverse travel along said slot upon longitudinal movement of saidindicator means with said piston.
 2. A compression tester according toclaim 1 wherein said first-mentioned means comprises a T-shape, hollowcase and an elongated stem received within the vertical leg of the T,said stem including a central bore constituting said cylinder.
 3. Acompression tester according to claim 1 wherein said first-mentionedmeans comprises an elongated stem having a lower extremity adapted fordisposition within the central bore of a fitting cooperative with aspark plug port.
 4. A compression tester according to claim 1 andincluding screw adjustment means carried by said case and in engagementwith said bias means, said screw adjustment means being operable tocompress said bias means and thereby adjust the force exerted by saidbias means against said piston.
 5. A compression tester according toclaim 1 wherein said cylinder includes a seat, and wherein said testerfurther comprises holding valve means upon said seat, and holding biasmeans urging said holding valve means onto said seat, whereby testpressure is retained between said piston and said holding valve means.6. A compression tester according to claim 5 and including release valvemeans carried by said case in engagement with said holding valve meansand selectively operable to move and unseat said holding valve meansfrom said seat to enable said test pressure to escape.